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  System and method for adaptive control of variable valve lift tappet switchingUSPTO Application #: 20070240653Title: System and method for adaptive control of variable valve lift tappet switching Abstract: A method of controlling cylinder valve switching between a first valve condition and a second valve condition for transitioning between combustion modes of an engine comprises adjusting timing of a signal to switch between said valve conditions in response to information from a combustion sensor, wherein said combustion modes include spark ignition and homogeneous compression ignition. (end of abstract) Agent: Alleman Hall Mccoy Russell & Tuttle, LLP - Portland, OR, US Inventor: Themi Philemon Petridis USPTO Applicaton #: 20070240653 - Class: 123090160 (USPTO) Related Patent Categories: Internal-combustion Engines, Poppet Valve Operating Mechanism, With Means For Varying Timing, Cam-to-valve Relationship The Patent Description & Claims data below is from USPTO Patent Application 20070240653. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD [0001] The present application relates to systems and methods for control of variable valve lift tappet switching during transition of combustions modes. BACKGROUND AND SUMMARY [0002] Engines may use various cylinder intake and/or exhaust valve profiles to improve engine operation over a range of conditions. For example, engines may use variable valve timing, cam profile switching, and others to provide different valve operation. Switches between the different valve profiles are typically controlled via hydraulic circuits, which may have variable delays. These delays can result in valve operation different than that desired for a given combustion event. [0003] One approach considering the delay of an oil circuit for changing valve characteristics is described in U.S. Pat. No. 6,330,869 where the combustion before and after the changeover of valve operation is a spark ignited combustion. In this reference, the property of the working oil in the hydraulic valve characteristic changing mechanism of the valve moving apparatus is detected, and the delay time is altered in accordance with the detected property of the working oil to make a change of the valve operation coincide with the change of the combustion condition of the engine. [0004] However, the inventors herein have recognized disadvantages with such an approach, especially when applied to an engine changing combustion modes during the switch in valve operation, such as between a spark ignition combustion and a compression ignition combustion. [0005] Specifically, there are numerous factors that may affect the valve switching and combustion modes. For example, the time delay may include factors such as delays in the electronic and solenoid valves. In addition, external conditions such as humidity or altitude may affect the response time of the tappet switch order required for transitioning combustion modes between different combustion modes, such as spark and compression ignition. Finally, errors in tappet switching may result in undesired combustion modes in cylinders and may cause engine misfires in a compression ignition mode, for example. [0006] Thus, in one approach, the above issue may be addressed by a method of controlling cylinder valve switching between a first valve condition and a second valve condition for transitioning between combustion modes of an engine. The method comprises adjusting timing of a signal to switch between said valve conditions in response to information from a combustion sensor, wherein said combustion modes include spark ignition and homogeneous compression ignition. [0007] In this way, it is possible to compensate for dynamics of the oil circuit and the delay in electronic components via combustion sensor information. Thus, it is possible to provide accurate control of a valve switching order during transition of combustion modes, thereby reducing torque fluctuations, emission spikes, vibration and audible noise. In one embodiment, information as to the timing of when each tappet has switched may be used to provide appropriate signal timing so that the correct amount of fuel can be injected into the respective cylinder, and the required temperature and pressure can be achieved inside the cylinder to perform desired combustion modes such as HCCI and SI. [0008] Furthermore, learned modifications to the switching time and/or order may be achieved enabling adaptation over time based on information from a combustion sensor to account for system degradation as well as external conditions such as humidity or altitude. DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 shows an example engine cylinder configuration; [0010] FIGS. 2A-B show detailed views of example combustion chambers; [0011] FIG. 2C shows a detailed view of an example tappet for use with the example of FIG. 2B; [0012] FIG. 3 illustrates example lift profiles; [0013] FIGS. 4-5 show example hydraulic actuator circuits for controlling actuation of multi-cylinder valve actuator systems; [0014] FIGS. 6-7 show example timing diagrams and timing windows for the example configuration of FIG. 4; [0015] FIGS. 8-9 show example timing diagrams and timing windows for the example configuration of FIG. 5; [0016] FIG. 10 shows an example flow chart for adaptive control of valve lift tappet switching; [0017] FIG. 11 shows an example flow chart for adaptive control of valve operations where multiple signals are used to control an oil circuit; and [0018] FIG. 12 shows a schematic graph of baseline correlation of crank angle to send switch signal with engine speed and adapted calibration over time. DETAILED DESCRIPTION [0019] FIG. 1 shows one cylinder of a multi-cylinder engine, as well as the intake and exhaust path connected to that cylinder. Continuing with FIG. 1, direct injection internal combustion engine 10, comprising a plurality of combustion chambers, is controlled by electronic engine controller 12. Combustion chamber 30 of engine 10 is shown including combustion chamber walls 32 with piston 36 positioned therein and connected to crankshaft 40. A starter motor (not shown) is coupled to crankshaft 40 via a flywheel (not shown). Combustion chamber, or cylinder, 30 is shown communicating with intake manifold 44 and exhaust manifold 48 via respective intake valves 52a and 52b (not shown, see FIG. 2), and exhaust valves 54a and 54b (not shown, see FIG. 2). Fuel injector 66A is shown directly coupled to combustion chamber 30 for delivering injected fuel directly therein in proportion to the pulse width of signal fpw received from controller 12 via electronic driver 68. The fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber, for example. Fuel is delivered to fuel injector 66A by a conventional high pressure fuel system (not shown) including a fuel tank, fuel pumps, and a fuel rail. [0020] Intake manifold 44 is shown communicating with throttle body 58 via throttle plate 62. In this particular example, throttle plate 62 is coupled to electric motor 94 so that the position of throttle plate 62 is controlled by controller 12 via electric motor 94. This configuration is commonly referred to as electronic throttle control (ETC), which is also utilized during idle speed control. Continue reading... Full patent description for System and method for adaptive control of variable valve lift tappet switching Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System and method for adaptive control of variable valve lift tappet switching patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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